Setting up shadowing on hair

Learning Resources > Tutorials > Getting Started with Maya Unlimited > Hair > Lesson 1: Creating a basic hairstyle >

Hair, by default, is translucent so you need to set up self shadowing, otherwise hair appears glowing, like nylon. The darker the hair color is, the more important the specular color and highlights become.

There are three directional lights in this scene. In the software render you did in the previous steps, Marion’s hair appears blond and glowing, even though the default hair color is dark brown, as in the scene view. This apparent hair color discrepancy occurs because:

hair is by default translucent (like a glass tube)
the hair is being lit by all three lights, therefore the intensity of the light is tripled
there are no shadows, so all the hairs are illuminated

In these next steps you set up shadows on all three lights.

To set up shadows and self shadows on hair

Select Window > Outliner.
In the Outliner menu, select Show > Objects > Lights.
Select one of the three directional lights.
In the light’s Attribute Editor, go to the Shadows section and in the Depth Map Shadow Attributes subsection, turn on Use Depth Map Shadows.
Normally you would increase the Filter Size to blur the light in the hair for realism, and increase the Bias, which sets how far the light filters through the hair. These attributes were set for you in the scene.
Repeat steps 3 and 4 for the other two directional lights.
Render the hair to see the changes.
The shadows on the hair are hard and there is very little specularity. You fix this in the next steps.

To create specular highlights on hair

To select the hair system, drag around the hair curves and select Hair > Convert Selection > to Hair Systems.
Go to the Shading section in the hairSystemShape1 tab of the Attribute Editor and set the following:
- Click the Specular Color box and set the values as shown in the image below.
- Increase Specular Power to 15.
Render the hair to see the changes. The hair looks much more natural now.